On the one hand, we have Kiva. Just in case you haven't heard of it, Kiva provides a way for investors to give micro-loans to entrepreneurs in developing countries, and it has an almost 100% payback rate. So you donate a little bit of money so a shop owner in Columbia can buy more merchandise to grow their shop and they pay you back quickly and completely. This isn't giving someone a fish, or even teaching them how to fish. This is helping them start a fishing business. Then they can hire people and contribute to their own countries in economy and it's just a growing snowball of awesomeness. In terms of giving to the world, this is one of the best ways I can think to do it.
And also there is Kickstarter. In my mind this is the opposite end of the spectrum, the first place I would go to grow a career or business. Or you can donate here as well to budding artists, so its another good use of money. Anyway, Kickstarter is a website for what is called crowd funding, which means that instead of going to a tiny group of wealthy investors who give you a big lump sum (and take things over in the meantime), you make it generally available for the "crowd" to fund you with smaller donations. So on Kickstarter you have a bunch of artistic people working on documentaries or art projects or a bunch of other cool things who have to fund their projects, and you can find ones you like and donate a little money. Enough people donate and boom, you're funded.
Again, like I said, I haven't used these sites yet myself, so I'm not sure on the specifics and more research is warranted. But definitely look into these sites, because they are just plain awesome. Check em out.
Also, in yesterdays comments it turns out a lot of people haven't heard of John Green. My assumptions were wrong :) But anyway, I wanted to make sure to clarify. John Green is, obviously, a writer, who writes young adult contemporary that is AWESOME! (Which is what the A in DFTBA stands for. The other letters stand for "Don't Forget To Be") He also vlogs with his brother Hank, and his vlogs are awesome. I wanted to leave you with my favorite of his videos, so here goes: (The yellow chart and boxes are from when he signed every pre-ordered copy of The Fault In Our Stars, which, when you have as many preorders as he did, is a major feat)